Z-stud structural member

ABSTRACT

A structural member “( 10 )” comprises a generally Z-shaped cross section. Two flange members ( 14, 16 ) are bonded to opposite sides and opposite ends of a diagonal web “( 12 )”. Each flange member “( 14, 16 )” has one surface “( 28 )” which is bonded to the web “( 12 )” and at least two additional surfaces “( 30, 32 )” at right angles to one another. The cross section of the web is six sided, each end of the cross section including a side which is continuous with one of the right angled sides of its associated flange member and another side which acts as a side load bearing surface for the structural member.

TECHNICAL FIELD OF THE INVENTION

This invention relates to structural members adapted to be used asbeams, joists, studs, posts, lintels, columns or as base and top platemembers.

BACKGROUND OF THE INVENTION

It is known to provide composite structural members designed to reducethe amount of solid wood fiber used and to improve the load bearingcapacity of the member, as compared to solid lumber. U.S. Pat. No.5,079,894 to Lau discloses such a structural member having a X-shapedcross section and comprising two isosceles triangle-shaped flangesbonded to opposite sides and ends of parallelogram-shaped web.

However, Lau's use of wedge-shaped flanges and a parallelogram-shapedweb limits the load bearing capacity of the member on two of its foursides as such loads are borne on the narrow longitudinal edges of theflanges and web. This in turn limits the ability to use the member inhorizontal load bearing applications, or to effectively combine severalsuch members in side by side relationship to form multi-unit compositemembers such as would be useful for example to produce posts or columns.

Lau also suggests that the flanges of the structural member may beproduced simply by diagonally (WORD USED BY LAU) halving 2×3 or 2×4lumber to produce two isosceles triangular wedges. But in fact, morethan one cut would be required to do so. As a result, fabrication of thestructural member is not as simple as Lau suggests, nor is it as costeffective as is the present invention in terms of manufacturing steps orthe volume of solid wood fibre consumed per unit.

It is therefore an object of the present invention to provide animproved composite structural member made of wood or wood fibre productswherein economical use of solid wood fibre is made and which isrelatively easy to manufacture. It is yet a further object of theinvention to provide a simple method of producing a composite structuralmember from solid lumber having standard dimensions.

It is a further object of the invention to provide a compositestructural member which has good load bearing capacity on substantiallyall of its sides and which is capable to being combined with other suchmembers into a multi-unit member.

It is yet a further object of the invention to provide a useful crosssectional profile of a structural member which may selectively be madeusing materials other than wood or using a combination of wood and suchother materials.

SUMMARY OF THE INVENTION

According to the preferred embodiment of die invention, a structuralmember is provided comprising a generally Z-shaped cross section. Twoflange members are bonded to opposite sides and opposite ends of adiagonal web. Preferably, the flange members and the diagonal web aremade of wood or wood fibre products and “the flange” members are cutfrom standard dimensional lumber.

Each flange member has one surface which is bonded to the web and atleast two additional surfaces at right angles to one another. The crosssection of the web is six sided, each end of the cross section includinga side which is continuous with one of the right angled sides of itsassociated flange member and another side which acts as a side loadbearing surface for the structural member.

In another aspect of the invention, the structural member has a crosssectional profile which is defined within an imaginary rectangle, andhas a diagonal web member and two flange members disposed on oppositesides of the web member. Each of the flange members has two sides whichare coplanar with the sides of the imaginary rectangle and the webportion has at least four surfaces which are coplanar with the sides ofthe imaginary rectangle.

In another of its aspects, the invention comprises a composite assemblyof such structural members secured in side by side relationship. This isparticularly useful when each structural member has a cross sectionalprofile whose longer side has a length which is an even multiple of thelength of its shorter side.

According to a method of making the structural member according to theinvention, a piece of solid lumber having a rectangular cross-section issectioned so as to produce at least two equal segments. Each hasinterior angles consisting of two right angles, one acute angle and oneobtuse angle. An elongated web having a generally rectangular crosssection and two opposed planar surfaces is provided. Two longitudinalcuts are made obliquely across the planar surfaces of the websubstantially at one edge of the web. The two cuts are at a right angleto one another. Two additional longitudinal cuts are made obliquelyacross said planar surfaces substantially at the other edge of the web.They too are at a right angle from one another. The at least two equalsegments are then bonded to opposite sides and opposite ends of saidweb.

The sectioning step described above may in fact produce only two equalsegments by performing a single longitudinal oblique cut through thecentral longitudinal axis of the lumber. Four or more equal segments mayalso be obtained depending on the width of the lumber and the desireddimensions of the resulting structural member. In the case of four equalsegments, the sectioning step of the method comprises the steps of:

longitudinally sectioning said piece of lumber into two equal pieceseach having a rectangular cross section;

longitudinally sectioning each of said two equal pieces with an obliquecut so as to produce four of said equal segments.

The present invention minimizes the use of solid wood, presents goodside load and end load bearing capacity, allows composite structuralmembers to be produced and provides the advantage of ease of manufacturewith a minimum number of cuts.

In another of its aspects, the invention comprises an elongated,integrally formed structural member having cross section comprising adiagonal web portion having major opposed planar surfaces, and two edgeportions extending along opposite lateral edges of said web member,characterized in that each of said edge portions comprises two paralleland spaced surfaces extending in a same direction from said web portion,and a third surface extending perpendicularly to said two parallelbetween the ends of said two parallel surfaces. The web portion includesat least two surfaces which are parallel to said third surfaces.

Other aspects of the invention will be appreciated by reference to thedescription of the preferred embodiments which follows and to theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more fully appreciated by reference to thefollowing description of the preferred embodiments thereof inconjunction with the drawings wherein:

FIG. 1 is a perspective view of a structural member according to thepreferred embodiment of the invention;

FIG. 2 is a cross sectional view of a structural member according to thepreferred embodiment of the invention;

FIG. 3a is a cross sectional view of a multi-unit composite structuralmember according to one embodiment of the invention;

FIG. 3b is a cross sectional view of a multi-unit composite structuralmember according to another embodiment of the invention;

FIG. 3c is a cross sectional view of a multi-unit composite structuralmember according to yet another embodiment of the invention;

FIG. 3d is a cross sectional view of a multi-unit composite structuralmember according to a further embodiment of the invention;

FIG. 4a is a cross section diagram of the cuts to be applied to anominal 2×6 piece of lumber according to the preferred embodiment of themethod invention;

FIG. 4b is a cross section diagram of the cut to be applied to adifferent piece of dimensional lumber;

FIG. 4c is a cross section view of two composite structural membersproduced according to the preferred embodiment of the invention;

FIG. 5 is a cross section diagram of the cuts to be applied to anotherwise rectangular web member according to the preferred embodimentof the invention.

DETAILED DESCRIPTION OF THE BEST MODE AND PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of the structural member 10 according tothe preferred embodiment of the invention. The structural member 10generally comprises an elongated web 12 and taco elongated flanges 14and 16. The two flanges 14 and 16 are disposed at opposite sides 18, 20and opposite ends 22, 24 of the web 12, which is disposed diagonally.The flanges 14, 16 are bonded to the web 12, preferably by an adhesive.

The web 12 and flanges 14, 16 are preferably made of wood or a woodbased composite, such as oriented strand board, plywood, particleboard,etc. In the preferred embodiment, the web is made of oriented strandboard and the flanges are cut from solid dimensional lumber.

The structural member 10 presents a generally Z-shaped cross section, asbest appreciated by reference to FIG. 2. The overall cross section ofthe structural member 10 is defined within an imaginary rectangle 26,shown in dashed lines. For greater clarity and the imaginary rectanglehas been shown as slightly enlarged.

The cross section profile of each of flanges 14, 16 is in the shape of aobliquely truncated rectangle, i.e. a quadrilateral having interiorangles consisting of two right angles, an acute angle and an obtuseangle. Each flange 14, 156 has an oblique surface 28 which is bonded tothe web and two additional surfaces 30, 32 disposed at right angles toone another. “The right-angled” surfaces 30, 32 are co-planar with twoof the sides 34, 36 of the imaginary rectangle 26. A filer surface 33 isparallel to surface 30.

The surface 30 defines the majority of the end surface 31 of thestructural member 10. Surface 32 forms a portion of the side surface 35of the structural member. The oblique surface 28 is at an acute angle tosurface 30. The surface 33 is parallel to surface 30, is shorter thansurface 30 and 28 and is at an obtuse angle to surface 28. Surface 32 isperpendicular to surfaces 30 and 33 and is shorter than surfaces 30 and33.

The web includes two major planar and opposed parallel surfaces 18, 20.The cross sectional profile of the web 12 is six sided, and moreparticularly is in the shape of an elongated two right angled hexagon.The cross section of the web 12 is defined about a lateral axis 38 whilethe longitudinal axis of the web extends into FIG. 2. Each lateral edge22, 24 of the web includes a surface 44 which is co-planar with one ofthe right angled surfaces, namely surface 30. Lateral edges 22, 24 formpart of the end surface 31 of the structural member. The web alsoincludes another surface 46 which is perpendicular to surface 44, formspart of side surface 35 and acts as a side load bearing surface for thestructural member. It will be appreciated that surfaces 44 and 46 areco-planar with two of the sides of the imaginary rectangle 26. Similarlysurfaces 30, 32 of the flanges are also co-planar with two sides of theimaginary rectangle 26.

Construction of Structural Member

The structural member 10 may be economically produced by providing anelongated piece of solid dimensional lumber having a rectangularcross-section, and obliquely cutting it along its length so as to derivefour equal segments 52, 54, 56 and 58, as shown On FIG. 4a. Such anapproach uses the entire piece of lumber and therefore involves nowastage of wood. Segments 52, 54, 56 and 58 will act as flanges for twostructural members 10 as shorn in FIG. 4c.

An elongated piece of dimensional solid lumber having a relativelyshorter rectangular cross section than the one illustrated in FIG. 4amay be sectioned to produce two equal flange segments 52 and 54 byperforming a single oblique cut along the central longitudinal axis ofthe member, as illustrated in FIG. 4b.

Regardless of whether two, three, four or more equal segments areproduced from a single piece of dimensional lumber, each of theresulting segments should have interior angles consisting of two rightangles, one acute angle and one obtuse angle, so as to be in the form ofan obliquely truncated rectangle or an obliquely truncated square.

Referring now to FIG. 5, an elongated web 12 is then provided which hasa generally rectangular cross section and two opposed planar surfaces18, 20. The web 12 is first cut along its length with the cut 60extending obliquely across the planar surfaces 18, 20. A secondlengthwise cut 62 is then made at a right angle to the first cut 60.

Referring to FIG. 4c, two flange segments are then bonded by adhesive toopposite sides and opposite ends of the web. An alternative approach tocutting the web 12 is to first perform two oblique cuts 60(corresponding to surface 44 in FIG. 2, bonding the flange elements tothe web, then performing cuts 62 (corresponding to surface 46 in FIG. 2)after the bond has set.

Where one piece of lumber is sectioned to produce four flange elementsas illustrated in FIG. 4a, all four elements can be used to produce twostructural members (FIG. 4c).

It will be appreciated that this method of constructing the structuralmember, in conjunction with the particular structure of the flanges andweb, allows for easy manufacture, with full use of the lumber used tomake the flanges and with a minimum of cuts.

As noted above, the flanges and web member are bonded together usingadhesives. Preferably, the bonding surfaces are textured in such manneras to increase the bond surface area between adjacent members. iforiented strand board is used for the web 12, a texturing processallowing for actual deformation through several layers of the webmaterial provides more effective adhesion. In the preferred embodimentof the invention this is accomplished by a knurling process applied tothe surfaces of both the web and the flanges which are to be bonded. Theknurling preferably extends to a depth of at least a few layers into theoriented strand board and a corresponding depth into the flange member.

The following parameters of the structural member may be varied whilestill embodying the principles of the invention:

the angle of the web to the vertical and the corresponding angle of thecut of the surface 28 of the Range

the width (thickness) of the web

the length of the side load bearing surface 44 of the web

the length of the right angled sides 30, 32 of the flanges

These parameters are largely interdependent.

The following provides a specific example of the dimensions involved inthe preferred embodiment of the invention. A nominal lumber size inNorth America is 2×6. FIG. 4a illustrates the cuts applied to a nominal2×6 piece of lumber. Looking at the butt end and orienting the sectionas shown in FIG. 4a the actual dimensions of the section prior tocutting are approximately 1.5 inches high and 5.5 inches wide. The mostpractical embodiment of the invention using nominal 2×6 lumber as asource of material for the flanges is to produce a structural memberhaving a cross section defined within an imaginary rectangle having aheight of 1.833 inches and a width of 5.5 inches. In order to make theflanges, the 2×6 lumber is longitudinally ripped three times at anglesof 17.0, 0 and 17.0 degrees to the vertical as shown in FIG. 4a suchthat each resulting flange section has a surface 32 having a length of1.5 inches, a surface 30 having a length of 1.529 inches and a surface33 having a length of 1.070 inches. The cuts are made such that thecentre of the saw kerf passes through the intersections of an imaginaryhorizontal bisecting line 51 and three vertical quadrasecting lines 53,55 and 57.

A first vertical cut at 0 degrees to the vertical bisects the 2×6 suchthat the centre of the saw kerf passes through the intersection of theimaginary horizontal 51, and ,vertical medial lines 55, to yield twoelongated rectangular sections. A second and third angular cuts at 17degrees, are made such that the centre of the saw kerf passes throughthe intersections of the imaginary horizontal 51, and vertical mediallines 53 and 57, to produce quaduplicate flange sections 52, 54, 56, 58.Solaces 28 of the resulting sections are then bonded to opposite ends 22and 24 and opposite faces 18 and 20 of the elongated web sections 12.The resulting composite structural members as shown in FIG. 4c, of whichthere are two, have a web component which is inclined at a 17 degreeangle and opposing flange elements of which surfaces 30 and 32 areparallel and coplanar with sides 34 and 36 of the imaginary rectangle26. It can be readily appreciated that two composite structural membershave been made from one solid 2×6 (nominal) piece of lumber and the webmaterial.

A composite structural member can also be made by providing an elongatedrectangular section having an approximate height of 1.5 inches and widthof 2.75 inches (a nominal size of 2×3) such as is shown in FIG. 4b. Thelumber section is bisected a such that the centre of the saw kerf passesthrough the intersection of the imaginary horizontal 51, and vertical 59medial lines. The two resulting flange elements are bonded, as notedabove, to a single web section 12 to produce a single compositestructural member having the same dimensions as noted above.

Composite structural members having a nominal size of 2×4, (1.75 incheshigh by 3.5 inches wide) can also be made from the same source materialsas shown in FIGS. 4a (2×6) and 4 b (2×3) by increasing the slope of theangular cut(s) through the medial line intersections from 17.0 degreesto 27.93 degrees. Resulting flange elements, 52, 54, 56 and 58 arebonded to web sections 12 which have been cut such that the width ofsurface 44 “(see FIG. 2)” is approximately 0.159 inches and surface 46is approximately 0.50 inches. The resulting composite structural membershave a web component which is inclined at a 27.93 degree angle andopposing flange elements of which surfaces 30 and 32 are parallel andcoplanar with sides 34 and 36 of the imaginary rectangle 26. Sides 31would be 1.75 inches wide and sides 35 of the section would be 3.5inches.

By varying the angle of the cut, the width of surfaces 44 and the heightof surfaces 46, a composite structural member of any desired dimensionmay be obtained from a suitable piece of source material. Further, theprocess of finger jointing or similar methods may be applied to theflange and web sections so as to create a composite structural member ofindefinite length which may then be cut into desired lengths.

Multi-unit Composite Members

Two composite members formed by the web and flanges described in thepreceding paragraph may be secured in side by side relationship as shownin FIG. 3a, 3 b, 3 c and 3 d to produce multi-unit structural memberswhich may serve as a beam, lintle, post or column. The process ofcombining structural members may be repeated until the required width ofbeam, etc. is attained. Preferably, the height 35 of the structuralmember is an even multiple of the width 31. Such even multiple allowsthe combination of structural members to create composite multi-unitmembers which are square as shown in FIG. 3c and 3 d. It will beappreciated that planar surfaces 46 provide abutment surfaces for oneanother, and also act as side load bearing surfaces for the individualstructural members. Thus, the individual structural members 10 are welladapted to form such composite multi-unit structural members. FIG. 3billustrates a different embodiments composite multi-unit members.

The structural member according to the invention is more resistant tobending when in a vertical application than conventional soliddimensional lumber due to its increased width. It is also lighter inweight as it uses less solid wood fibre.

The configuration of the structural member is such that the bulk of themass is concentrated at the extremities of the section. This isadvantageous in that the section's moment of inertia, for an equivalentsize of structural member to that of the X-beam disclosed in U.S. Pat.No. 5,079,894, is equivalent while consuming less solid wood fibre.

As compared for example to the X-beam disclosed in U.S. Pat. No.5,079,894, which in its preferred embodiment would use a total of 63cubic inches of solid wood per linear foot of structural member, thestructural member of the invention uses 49.5 cubic inches of solid woodper linear foot of structural member based on the embodiment of theinvention illustrated in FIG. 2, using standard dimensional 2×6 lumber.

As the flange elements may usually be cut from standard dimensionallumber to yield an equal number of flange sections with little or nowastage, utilization of wood fibre is maximized. Further, round logs maybe cut in such a fashion so as to produce flange sections such as thoseshown in FIG. 4b from areas of the round log that otherwise would bewaste.

The advantages of the structural member described herein may also beachieved with flanges and a web made from materials other than wood orwood composites. In addition, the cross sectional Z-shaped profile ofthe structural member according to the invention -may also be usefullyapplied to a unitary member wherein the flanges and web described hereinare integrally formed, for example out of a single material. Such amember is characterized by comprising a diagonal web portion havingmajor opposed planar surfaces. Two edge portions extends along oppositelateral edges of said web member. Each of said edge portions comprisestwo parallel and spaced surfaces extending in a same direction from saidweb portion, and a third surface extending perpendicularly to said twoparallel between the ends of said two parallel surfaces. The web portionincludes at least two surfaces which are parallel to said thirdsurfaces.

It will be appreciated by those skilled in the art that modificationsand variations may be practised on the preferred embodiments describedherein without nonetheless departing from the principles of theinvention or the intended scope of the claims.

What is claimed is:
 1. A structural member having a diagonal web memberhaving major opposed planar surfaces, and two flange members bonded torespective ones of said major surfaces along opposite lateral edges ofsaid web member, characterized in that: each of said flange memberscomprising a first surface bonded to one of said major surfaces, secondsurface at an acute angle to said first surface, a third surface at aright angle to said second surface, and a fourth surface parallel tosaid second surface; said web member has a six-sided cross section, andcomprising said major opposed planar surfaces, a third web surface whichis coplanar with said second surface of a first one of said flangemembers, a fourth planar web surface at a right angle to said third websurface, a fifth planar web surface which is coplanar with said secondsurface of a second one of said flange members, and a sixth planar websurface at a right angle to said fifth web surface.
 2. A structuralmember having a diagonal web member having major opposed planarsurfaces, and two flange members bonded to respective ones of said majorsurfaces along opposite lateral edges of said web member, saidstructural member having a cross-sectional profile defined within animaginary rectangle, characterized in that: the cross sectional profileof each of said flange members has two sides which are coplanar with thesides of said imaginary rectangle and the cross sectional profile ofsaid web member has four sides which are coplanar with the sides of saidimaginary rectangle.
 3. A structural member as in claim 1 wherein saidthird surface is shorter than said first surface.
 4. A structural memberaccording to claim 1, 2 or 3 further characterized in that said flangesand said web are made of wood or wood composite materials.
 5. Acomposite assembly of structural members according to claim 1, 2, 3 or 4comprising at least two of said structural members secured to oneanother in side by side relationship.
 6. A composite assembly accordingto claim 5 wherein the cross sectional profile of each structural memberhas a length which is approximately an even multiple of its width.
 7. Amethod of making a composite structural member comprising the steps of:sectioning a piece of solid lumber having a rectangular cross-section soas to produce at least two equal segments, each of said segments havinginterior angles consisting of two right angles, one acute angle and oneobtuse angle, providing an elongated web having a generally rectangularcross section and two opposed planar surfaces; performing twolongitudinal cuts extending obliquely across said planar surfacessubstantially at one edge of the web, said cuts being at a right angleto one another; performing two additional longitudinal cuts extendingobliquely across said planar surfaces substantially at the other edge ofthe web, said two additional cuts being at a right angle to one another;bonding by adhesive said at least two equal segments to opposite sidesand opposite ends of said web.
 8. The method of claim 7 furthercharacterized in that said step of sectioning comprises only the step ofperforming a single longitudinal oblique cut through the centrallongitudinal axis of the lumber.
 9. The method of claim 7 wherein saidstep of sectional said piece of lumber into at least two equal segmentscomprises the steps of: longitudinally sectioning said piece of lumberinto two equal pieces each having a rectangular cross section;longitudinally sectioning each of said two equal pieces with a obliquecut so as to produce four of said equal segments.
 10. The methodaccording to claim 7 wherein said second and fourth longitudinal cutsare performed after said step of bonding the segments to the web.
 11. Anelongated, integrally formed structural member having cross sectioncomprising a diagonal web portion having major opposed planar surfaces,and two edge portions extending along opposite lateral edges of said webmember, characterized in that: each of said edge portions comprises twoparallel and spaced surfaces extending in a same direction from said webportion, and a third surface extending perpendicularly to said twoparallel between the ends of said two parallel surfaces; and, said webportion includes at least two surfaces which are parallel to said thirdsurfaces.